Guideline on Use of Nitrous Oxide for Pediatric Dental Patients

Resident: Cho

Author(s): Council on Clinical Affairs

Journal: AAPD Reference Manual

Year. Volume (number). Page #’s: 2010-11

Major topic: Nitrous Oxide

Type of Article: Reference Article

Main Purpose: To assist the dental profession in developing appropriate practices in the use of nitrous oxide for pediatric patients.

Methods: A MEDLINE search was conducted using the terms “nitrous oxide”, “analgesia”, “anxiolysis”, “behavior management”, and “dental treatment”.

Key points/Summary:

Background:

Nitrous oxide is a colorless and virtually odorless gas with a faint, sweet smell. It is an effective analgesic/anxiolytic agent causing CNS depression and euphoria with little effect on the respiratory system. It is relatively insoluble, passing down a gradient into other tissues and cells in the body, such as the CNS. It is 34 times more soluble than nitrogen in the blood.

Objectives of nitrous oxide:

Reduce or eliminate anxiety, reduce untoward movement and reaction to dental treatment, enhance communication and patient cooperation, raise the pain reaction threshold, increase tolerance for longer appointments, aid in treatment of the mentally/physically disabled or medically compromised patient, reduce gagging, potentiate the effect of sedatives.

Disadvantages of nitrous oxide:

Lack of potency, dependent largely on psychological reassurance, interference of the nasal hood with injection to anterior maxillary region, patient must be able to breathe through the nose, nitrous oxide pollution and potential occupational exposure health hazards.

Patient selection:

A fearful, anxious, or obstreperous patient

Certain patients with special health care needs

Gag reflex interferes with dental care

Patient for whom profound local anesthesia cannot be obtained

Cooperative child undergoing lengthy procedure

Review of medical history should be performed prior to decision to use nitrous oxide.

Contraindications for nitrous oxide:

Chronic obstructive pulmonary disease

Severe emotional disturbances or drug-related dependencies

First trimester of pregnancy

Treatment with bleomycin sulfate (drug used to treat cancer)

Methylenetetrahydrofolate reductase deficiency

When considering patients with significant medical conditions (ex. severe obstructive pulmonary disease, CHF, sickle cell disease, acute otitis media, recent tympanic membrane graft, acute severe head injury), physician should be consulted.

Techniques for nitrous oxide:

Flow rate of 5 to 6L/min generally acceptable – flow rate should be adjusted after observation of reservoir bag. Introduction of 100% oxygen for 1-2 minutes followed by titration of nitrous oxide in 10% intervals is recommended. The concentration of nitrous oxide should not routinely exceed 50%. The effects of nitrous oxide is largely dependent on psychological reassurance, therefore, it is important to still continue traditional behavior guidance techniques during treatment. Diffusion hypoxia may occur (as a result of rapid release of nitrous oxide form the blood stream into the alveoli, thereby diluting the concentration of oxygen – leading to headache and disorientation), therefore, 100% oxygen for 3-5 minutes must be given at the end of the appt. Patient must return to pretreatment responsiveness before discharge.

Monitoring:

Clinical observation of patient’s responsiveness, color, RR, and rhythm must be performed. Spoken responses provide an indication that the patient is breathing.

Adverse effects of nitrous oxide:

Nitrous oxide has an excellent safety record. Most common adverse effect is nausea/vomiting, which occurs in 0.5% of patients. A higher incidence is noted with a longer administration of nitrous oxide, fluctuations of nitrous oxide levels, and increased concentrations of nitrous oxide.

Fasting is not required before nitrous oxide. However, the dentist may recommend only a light meal be consumed 2 hours prior to nitrous oxide.

Informed consent must be obtained from the parent. The patient’s record should include indication for use of nitrous oxide, flow rate, duration of the procedure, and post treatment oxygenation procedure.

Facilities:

All newly installed facilities for delivering nitrous oxide must be checked for proper gas delivery and fail-safe function prior to use. Inhalation equipment must have the capacity for delivering 100% oxygen and never less than 30% oxygen. The equipment must have an appropriate scavenging system. Proper BLS training is required for all personnel using nitrous oxide and an emergency kit must be readily accessible. A positive-pressure oxygen delivery system capable of administering >90% oxygen at a 10L/min flow for at least 60 minutes must be available. There should be documentation that all emergency equipment and drugs are checked and maintained on a regularly scheduled basis.

Assessment of Article: I was surprised that the article did not mention the use of blood pressure cuffs and pulse oximeters for monitoring the patient when using nitrous oxide. Great article!